Thanks PK Another timer chip Version - http://www.vk2bv.org/w_ctcss.htm http://www.vk2bv.org/p_fig2a.gif This is the one the NREG guys made a few years ago. It decodes and encodes but is fixed in frequency. I've done a PCB in eagle cad and got the parts for a prototype of this one. OpAmp Version - http://www.fenlandrepeater.org.uk/ctcss.htm I'm a bit dubious about the stablity of this design. MX315 Version - http://www.com-spec.com/selectone/manual/st_133b.pdf (Ni impossible to loacte the chip here in Australia) I've got a st-140 arrounfd here that I pulled out of an old Willis that I've got to send to Rick Vk4sw. 12C508 Version - http://members.optushome.com.au/vk3biz/ctcss-tones.html THe PIC is a little harder to find hence I'm going to give the one below a bash as well..... 16F84A Version - http://users.picknowl.com.au/~wavetel/pic.htm I pretty well have evey thing for it. (EagleCAD files attached) Cheers Rod VK4UTE
